Present existing deicing products that are commonly used are: salt (sodium chloride), calcium chloride and urea, the latter two being more expensive than salt. Chloride salts suffer some drawbacks inter-alia, they accelerate corrosion resulting in damage to cars, trucks, and other vehicles; some are hazardous to the environment or expensive.
The use of about 11M tons of highway salt in North America accelerates motor vehicle corrosion rates to about twice that which would be expected if no salt was used according to articles entitled:
J. C. McBride, W. J. Kennedy, J. H. Thuet, M. C. Belangie and R. M. Stewart, "Economic Impact of Highway Snow and Ice Control (final report)", Utah Dept. of Transportation, Salt Lake City Research and Development Unit, Report No. UDOT-MR-77-5; FHWA/RD-77-95: December 1977. PA1 R. L. Chance, "Corrosion, Deicing Salts, and the Environment", Materials Performance, p. 16, October 1974. PA1 H. J. Fromm, "The Corrosion of Auto-Body Steel and the Effects of Inhibited Deicing Salts", Department of Highways, Ontario, Report No. RR135,(1967). PA1 "Deicing Salts, Their Uses and Effects", NACE Group Committee T-3, Report 3W175, Materials Performance 14 No. 4, 9 (1975).
This has caused automobile manufacturers to improve design, materials of construction and coating systems. Owner care and maintenance is also a critical factor in extending vehicle life.
The relatively rapid deterioration of concrete is in part a result of rebar (reinforcing steel) rusting accelerated by saline solutions in the concrete structure and their accumulation in pore water. Annual maintenace costs of reinforced concrete highways are certainly in the range of hundreds of millions, if not billions of dollars. In the last few years there has been increased research into alternative deicing chemicals, especially in the United States, with the objective of reducing the use of NaCl as road deicer in favour of materials that would be less harmful to vehicles, roads, plant and animial life, soils, etc. as NaCl is reported to be. The material being most extensively researched for use on highways to this point is calcium-magnesium acetate (CMA). While CMA may have the necessary properties of a deicer (i.e. among others it reduces the freezing temperature of water, and thus has ice-melting capabilities), its production cost is prohibitive when commercially available acetic acid is used in its manufacture. Research is in progress to reduce the manufacturing cost, however, a satisfactory process has not yet been demonstrated.